holley carb

[Clarkson]

Hi all,

I have a 350 chevy with a 600cfm holley that is over fueling on idle,with heavy black smoke on idle.I have adjusted the 2 mixture screws fully in with no change at all.

Does anyone have any ideas?
David Clarkson.

[robert]

Pull the unit off, dismantle and clean thoroughly, there might be some dirt under the needle seats, happened to me before.

[Clarkson]

Hi Rob,

Thanks for that Rob,but I done that last week.I started the engine today for the first time in a year.It's actually been doing this for nearly 10 years.I am thinking about buying a new carb,just thought if anyone has any ideas.;( ;( ;(

David clarkson

[robert]

>Hi Rob,
>
>Thanks for that Rob,but I done that last week.I started the
>engine today for the first time in a year.It's actually been
>doing this for nearly 10 years.I am thinking about buying a
>new carb,just thought if anyone has any ideas.;( ;( ;(

Yeah, buy a new carb......... :tu :tu

[mikey]

You need to check a few things.

Firstly that fuel is not being drawn past the metering block gaskets. Strip and check the main body for straightness with a steel ruler. If there is slight warp which is not uncommon you can repair with a sanding block (Ihave done this). Also check the small ribs tat pinch the gasket on the metering block are present. Tightness of the bowl scrtews is also critical.

Secondly check that the float heights are set correctly and that fuel is not coming up through the vent pipe at tickover.

It is also worth changing the power valve when you strip.

The other thing to check is the fuel delivery pressure from your pump. Is it too high so that your needles are being by-passed.

My advice is to get a genuine Holley rebuild kit and strip totally. Use re-usable gaskets for the metering blocks as the standard ones stick after a few hours use and you can not strip again without destroying the gasket. The kit contains new needle s etc. Do not be tempted to get a cheaper aftermarket kit as a number use low flow pwer valves that use two holes rather than slots.
Mike

[Clarkson]

Mike,

I bought a rebuild kit from real steel with no change at all.I changed the power valve and set the float heights with new gaskets.It's running about 7%co on idle and 3200hc.Now it's burning oil due to bore wash.

Tomorrow I am going to real steel again and buy a new carb!

Has anyone got any ideas wot carb to buy eg edelbrock or holley and can you run these engines lean with these carbs? surely it must run under 3%co?

Time for a bath, I stink of exhust fumes!

Help please!
David Clarkson.
:} :} :}

[callum]

If you want to carry on smelling of fuel and being a hotshot tuner buy a Holley. If you are a wimp who just wants to drive buy an Edelbrock. I fall into the latter category! Unless your SBC is highly tuned the 600cfm will be just fine - otherwise the 750. :tu

[Clarkson]

Cullum

What engine do you have? I take it you are happy with your edelbrock carb? What are yor emissons like?

[graham]

I had exactly this problem and it was solely down to the float levels. Get some see through sight level plugs and set the level whilst engine running ideally if you can keep it going. Later I did adjust the ign timing and mixture screws as running well to lean then. Seems about right now at least to get it run in then to a rolling road for a better set up post sva.

graham

[Clarkson]

Hi guys,

Today I went to Repower to buy my 600 edelbrock carb, and my god what a diffrence! I rechecked the emissions and now it idles at 600rpm with 1.5%co with 125hc.It runs very clean with no flat spots or hesitation whats so ever.I must have a faulty carb from day one.

See you all at stoneleigh.

David Clarkson.